The present invention generally relates to an improved injector assembly for a fuel injection system, as well to a fuel injection system incorporating the assembly. More particularly, the invention relates to fuel injection systems, particularly low pressure fuel injection systems, for internal combustion engines that incorporate one or more reed block assemblies having reed valves which substantially permit a one-way flow of air into the crankcase of the internal combustion engine. The fuel injector assembly also serves to securely mount the reed block assembly to its desired location within the internal combustion engine.
One-way reed valves and the like are known to be incorporated within internal combustion engines. The reed valves often are mounted in a bank or block-like arrangement in the form of a reed valve block assembly which is secured to a wall or the like of the engine in a manner such that the reed valves provide one-way passageways into the crankcase of the internal combustion engine. These passageways provide access of at least air into the engine crankcase while preventing backflow out of the crankcase and facilitating vacuum or low pressure conditions in a chamber or manifold upstream of the reed valve assembly.
In some internal combustion engines, the fuel is also injected into the chamber or manifold upstream of the reed valves. In an arrangement of this type, the intent is to atomize the fuel within the chamber, and the fuel and air mixture then flows through the various reed valves and into the crankcase for subsequent passage into a cylinder for combustion in accordance with generally known principles. One intended advantage of this type of an arrangement is that the fuel will automatically lubricate the petals of the reed valves. However, this type of an arrangement is not without its disadvantages. By passing the fuel through the reed valves, there is a tendency for the fuel to deposit within the reed valve assembly and thereby form a gum, which can reduce engine efficiency and cause an engine maintenance problem, especially when the engine is not used for extended time periods. This can lead to engine starting difficulties and can require periodic cleaning. Even in the absence of any substantial gumming, it has been determined that flowing fuel through the reed valve reduces the flow volume of air therethrough and can cause a reduction in the air which is available to flow to the cylinders. This reduction in total potential air flow volume through the reed valve banks generally translates into a loss of total potential horsepower that can be developed by the internal combustion engine.
Some internal combustion engines include arrangements that are designed to avoid problems created by passing the fuel through the reed valve bank. Publications such as Staerzl U.S. Pat. Nos. 4,305,351 and 4,763,626, the subject matter thereof being incorporated by reference hereinto, show low pressure electronic fuel injection systems wherein the fuel is injected directly into the crankcase at a location downstream of the outlet from the reed valve bank assembly. An approach such as this is also intended to minimize the development of a so-called puddling condition, which is prone to develop in the case of an outboard motor wherein cylinders are in a vertically stacked array. With vertically stacked cylinders, there is a tendency, due the influence of gravity, for the lower cylinders to receive a greater flow of fuel than do the upper cylinders, which can result in unduly enriched fuel-air mixtures in the lower cylinder or cylinders. Such a so-called puddling condition creates inefficiencies and impairs the ability of the engine to achieve its designed output.
Although devices such as these have made substantial progress in avoiding the so-called puddling condition, they too are not without disadvantages. For each fuel outlet downstream of the reed valve bank, an opening must typically be made through the engine block or crankcase wall. This increases manufacturing costs and gives rise to a potential maintenance requirement to ensure proper positioning of the injectors within the cylinder block or crankcase wall. In addition, this type of an arrangement requires fuel lines running to each injector at locations external of the engine. This type of fuel routing is considered to be aesthetically unpleasing due to the numerous external fuel lines connected to the various injectors downstream of the reed valve bank.
By the present invention, at least one fuel injection outlet is provided at a location adjacent to or immediately downstream of each reed valve block of an internal combustion engine. This is accomplished without having to pass each injector and/or fuel line through the engine block or crankcase wall of the internal combustion engine. In the apparatus according to the present invention, a fuel injector assembly is provided which also serves as a securement member for a reed valve block. Multiple fuel injector assemblies can be provided for each reed valve block that opens into the crankcase of the engine. Each fuel injector assembly includes a fuel injector or check valve which is supported by a fastener housing that also functions as a fastener mount by which a reed valve block is attached to the engine.
It is a general object of the present invention to provide an improved fuel injector assembly and a fuel injection system incorporating same.
Another object of this invention is to provide an improved fuel injector assembly which provides a fuel inlet site that opens into the crankcase of an internal combustion engine and by virtue of which fuel flow through reed valve blocks of the engine can be eliminated.
Another object of the present invention is to provide an improved low pressure fuel injection system for an internal combustion engine in which a fuel injector assembly thereof functions both as an injector and as a reed valve mounting device.
Another object of the present invention is to provide an improved fuel injector assembly which minimizes the likelihood that a puddling condition will develop, even in two-cycle multiple-cylinder engines for incorporation into marine outboard motors.
Another object of this invention is to provide a low pressure fuel injection system for an internal combustion engine which avoids aesthetically unattractive external fuel lines running to the engine block.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the followed detailed description.